Palestra 3 - Fabricação de moldes por micro-usinagem.

Manufacturing of micro-moulds

Benedikt Gellissen

Fraunhofer Institute for Production Technology IPT

International Seminar: Application of new technologies in the
metal mechanic sector

Joinville, Brazil, September 2011
© WZL/Fraunhofer IPT

Economic Developments in MST
The booming of micro Batelle (1990) SEMI (1995)
system technology (MST): 9 billion US$ 12 billion US$
8
10
7
- Main focus on industries 6 8
5
like life science, IT, bio- 4
6

and sensor technology 3 4
2
2
1
- Annual growth of 18% 91 93 95 98 00 94 95 96 97 98 99 00
from 1996 to 2002
SPC (1994) NEXUS (1998)
- Estimated growth of the 16 billion US$ 40 billion US$
14 35
market from 2002 to 2005 12 30
of 28 to 65 billion US$ 10 25
8 20
6 15
4 10
2 5

93 94 95 96 97 98 99 00 96 97 98 99 00 01 02

Source: NEXUS, VDI VDE-IT

© WZL/Fraunhofer IPT Page 1

Economic and Technical Developments
Patent analysis of MST Number of patent registrations
for microPRO Study 180
in 2002:
160
- Based on the 140
World Patent Index 120
- The following terms were 100
taken under consideration: 80
MST, Micro -mechanic,
60
-optic, -fluidic, -assembly,
UP- and micro machining 40
20
- 29.7% of the patent
categories come from the
field of plastics processing 90 91 92 93 94 95 96 97 98 99
USA (880) e.g. 23 Fraunhofer Gesellschaft
Indications of upcoming 21 Robert Bosch GmbH
Japan (445) 16 Institut für Mikrotechnik Mainz GmbH
mass production Germany (378) 15 Siemens AG

International comparison - microPRO Study
Switzerland
§ Predominantly affiliation of enterprises to mechanical engineering and precision engineering
§ Industrially practiced miniaturization is closely connected to the watch industry
§ Technical know-how is currently used to open up new market segments like
information and communications technology

USA
§ Strong influence by electronics production and semiconductor technology
§ High process automation demanded
(due to prevailing high quantities in the above named sectors)
§ Future market segments are seen in medical engineering, bio-technology and
in electro-optical products

Japan, Taiwan, Singapore
§ Company activities were focused on optics, electronics production and the
production of tools and machine tools
§ Trend towards integration of miniaturized systems into new (mass) products
§ Development of extremely downscaled machine tools and complete assembly systems

Summary of mikroPRO Study
§ Numerous applications of micro manufacturing technologies in various
industrial sectors

§ Broad basic research
- some excellent results in single manufacturing technologies

§ There are deficits in the transfer of the technologies into real products,
partly due to
- low industrial maturity of the manufacturing technologies
(process stability)
- lack of technological knowledge for the design and development
of new products (manufacturing specific design, technology limits,
design rules)
- limited accessible knowledge of industrial product and process
requirements


Typical branches –
MST are found in different branches with the tendency for mass production

Automotive industry Life sciences Telecommunication

- Sensor technology - Medical technology - Optical data transfer and
- Optical elements - Biotechnology coupling
for interior and exterior - Techniques for analysis - Display technology
- Micro mechanical devices - ... - ...
- ...

Source: Cooke Corp., microparts, Euronano


Due to developments in the industry -
MST is still a chance for mould and die makers
Precision Engineering Micro Electro-Mechanical
Systems (MEMS)

Micro Mould Making
Example of micro cast Micro channel Bioreactor
products (Source: FZK) Example of powder injection
molding products; gear Micro pumps
Detection
(MIM), (Source: IFAM) cell

Micro-structuring
10 µm

Test piece and human hair structured with dicing blades Measuring instrument for alcohol
(Source: Grundig) (Source: DISCO Corp.) (Source: IMT, TU Braunschweig)


Focus of this presentation –
Conventional Technologies in MST
Chip removal EDM Lasering
Diamond Carbide Wire-EDM Sink-EDM Nd:YAG
Workpiece Nickel Steel Metals Metals Metals
material Brass Ceramics (Ceramics) (Ceramics) Graphite
Aluminium Graphite Ceramics
Plastics
Lateral
10 - 1000 µm 10 - 1000 µm 20 - 50 µm 20 - 40 µm 5 - 1000 µm
structures
Aspect ratio 10 - 50 2 - 10 25 - 80 10 - 25 10 - 100
Geometric
++ ++ + + ++
freedom
Surface
quality Ra 0.01 µm 0.3 µm 0.04 – 0.06 µm 0.2 – 0.4 µm 0.1 – 1.3 µm

200µm 700mm 200µm 200mm 200µm


Production processes in MST –
Compromises and alignment with the costumer product

1 Silicon etching
Silicon etching (40%)
Laser
LIGA
5

Structure [µm]
Chip removal
Chip removal 10
(22%)
EDM Grinding
25

Grinding EDM
(9%) (16%) 50 Complexity of geometry
LIGA
(11%) planar freeforms

200 100 50 25 10 5
Surface roughness Ra [nm]
Source: IPA, ILT, IPT


Photolithography Etching of Silicon –
Advantages are clearly visible but the limitations too
industrial wave length min.
use of illuminate structure

1980 - 1986 436 nm 0.60 µm
1986 - now 365 nm 0.35 µm
1992 - now 248 nm 0.20 µm
1998 - now 193 nm 0.15 µm
R+D 157 nm 0.12 µm
R+D 013 nm 0.08 µm

Silicon dioxide
Source: Cranfield University, Zeiss
film to be etched


Typical products –
The requirements towards the products functionality is spread
widely
Facette mirror Intracardial blood pump Micro fuel cell

Reflecting structures Lab on a chip

Sources: Scholz, Impella, Wikipedia.de, Fraunhofer IPT


Plastics
Lateral
10 - 1000 µm 10 - 1000 µm 20 - 50 µm 20 - 40 µm 5 - 1000 µm
structures
Aspect ratio 10 - 50 2 - 10 25 - 80 10 - 25 10 - 100
Geometric
++ ++ + + ++
freedom
Surface

200µm 700mm 200µm 200mm 200µm


Micro Clip (Design)
Micro Clip for medical applications - Insert with electrodes
detail of clip mechanism
Electrode

•
Electrode
ƒ

Electrode
‚
Insert
Insert
Source: Zumtobel Staff

Challenges Solution to date Aim
- Steel mould insert - Complex fabrication and - Direct fabrication of
- Micro free-form surfaces positioning of the three the inserts by 5-axis
- Undercut of 54 µm electrodes micro milling

Micro Clip (Mould Insert)
Mould Insert (SEM image)

Feature A
with undercut

Feature A

200 µm
Source: Zumtobel Staff


Application -
Intracardiac Pump System
Intracardiac pump system
for patient-friendly and
economic treatment of
acute heart diseases
< Replacement of heart-lung
machines via intrabody
< No surgical intervention
< On site placement in the
heart through the leg artery
< Post operation heart
support for up to 7 days
< Outer diameter of pump 4.0
and 6.4 mm respectively
< Pump performance up to
Measurements:
4,5 l/min
3.55mm x 7.7mm
Source: Impella CardioSystems AGMaterial: PEEK


Recover® Technology: Manufacturing of Impeller
Former process: Five axis milling of
PEEK

Quelle: IBMT

< Single part manufacturing
< High effort for manual finishing
< Low reproducability


Recover® Technology: Manufacturing of Impeller
Former process: Five axis milling of Now: Injection moulding
PEEK

Source: Horst Scholz GmbH + Co. KG
Quelle: IBMT

< Single part manufacturing < Batch production
< High effort for manual finishing < Low effort for manual finishing
< Low reproducability < Extremely high reproducability


Manufacturing of Mould Inserts
Former process: Micro-EDM Now: Five axis micro milling

< High process knowledge < 5 axis manufacturing necessary
< Two-step process < One-step process
< Effort for manual finishing


Plastics
Lateral
10 - 1000 µm 10 - 1000 µm 20 - 50 µm 20 - 40 µm 5 - 1000 µm
structures
Aspect ratio 10 - 50 2 - 10 25 - 80 10 - 25 10 - 100
Geometric
++ ++ + + ++
freedom
Surface

200µm 700mm 200µm 200mm 200µm


UP-processes –
Structures and processes strategies

Face milling Fly Cutting

UP-Planing Turning


UP-planing-machine for large-scaled structured surfaces
n Ultraprecision machine for
the machining of large
workpieces by means of
diamond milling and
planing
n Max. working area
1000 x 1000 x 200 mm³
n Rotary table (C-axis)
n Hydrostatic bearings for all
axis (not realised in vertical
direction)
n Two portal slides for either
mass compensation or
usage of two tools
n Equipped with standard NC
controller


Manufacturing technology for micro and nano structures
Fly cutting Planing
Tool shaft
Tool
Diamond tool
Manufactured
surface

Vorschub

z x f -
Cut direction
Spindle rotation
a
a
p
Roughness
Part

n Tools: mono crystalline diamond
n Structure size 3 µm, surface roughness 10 nm Ra
n Highest form accuracy
n Work pieces up to 1 x 1 m2
n High manufacturing times for big parts


Fly-Cutting – Applications

100 mm
Masterstruktur
einer Beleuchtungs- 10 mm
optik Element eines Retroreflektors
10 mm 100 µm

Masterstruktur eines großflächigen
Heißprägewerkzeug Reflektors

0,5 mm 0,5 mm

2 mm 50 mm


Large area structuring with the fly-cutting process
n Long time machining
n Structure: triangular corner cubes (1 mm)
n Size of workpiece: 400 x 400 mm2
n Distance of cut: 6.15 km
n Machining time: 5.3 d
n Machined at tangential feed
n Investigation on tool wear

2 mm

Sample part with structure Machined master (CuNi18Zn20 400 x 400 mm2)

Hybrid optics

Sinus curve-surface Hybrid
FTS

10 mm
Facet mirror


Machine for the production of hybrid optics
n MTC
410
– Travel length of axis 410 mm
Fast Tool
– Max. work piece diameter 800 mm
– Total weight 3.800 kg
Case
– Dimensions 1900x1500x1500
Granite base
plate

Height
adjustment

B-axis

n Dynamic axis
– Total weight 90 kg
– Moving mass 10 kg
– Max. acceleration 62 m/sec²


Freeform reflectors - computable, but not to manufacture?
Reflector surface
Light source
n Freeform surface
Freeform-
n Scaleable geometry mirror Projection

n Diameter = 20 mm
n Non-rotationally symmetric
portion: 0,45 mm
n Data type: NURBS
(Non Uniform Rational B-
Splines) Simulated tool path NURBS-Mirror surface
Brightness distribution
Manufacturing requirements
y [mm]

n Harmonic tool path
n Very high frequency position
control
NC code correction

x [mm] Source: OEC AG

Summary –
Limitation of UP Machining
Ultra precision machining
with mono crystalline diamond tools
Recent developments
< ultra precision machining of nonferrous materials by
turning, milling and fly cutting
< extremely high surface quality of a few nanometers Ra
< shape accuracy in the submicron range

Restrictions
< machining of ferrous materials causes high wear
< life time of nonferrous metals cavities
is not sufficient in many cases
< galvanic process chain is time consuming, expansive
and with limited reproducibility

Galvanic layer separation There is a huge demand for flexible production
technologies to machine wear resisted mould inlays

Competitiveness
Precision Glass Molding vs. Alternative Manufacturing Technologie
Grinding and Polishing Precision Glass Molding Conventional Molding

– Oldest technology for – Technology for mass – Technology for mass
glass optics production production
manufacturing – Obtainable accuracy – Non-isothermal
– Large variety geometries satisfying for imaging
optics – Accuracies satisfying for
possible lighting optics
– Isothermal process
– Nearly all optical glasses – Limitation in glass
– Nearly all optical glass
machinable moldable material choice
– Highest accuracies – Ceramic molds – Geometric variability
obtainable – Accuracies in the range limited by mold
l to l/5 manufacturing


Precision Glass Molding:
An Integrative Approach

Data Handling

Optic FEM Mold Molded
Mold Design Molding
Design Simulation Manufact. Lens

Idea
n Optimization of the process sequence for precision glass molding towards higher
efficiency and more complex optical elements
n Generation of an integrated approach for the data handling

Concept
n Consideration of each single process step including the different interfaces


Precision Glass Molding
The Process
Process cycle Temperatur and force cycle
1. Loading and
N2-purging
Homogizing
N2 Gas Tg

2. Heating of glass IR -lamps Heating Cooling

Temperatur
and mold

Force
Pressing
Mold
3. Pressing
Time
F Force
Temperatur
4. Cooling and
unloading
N2 Gas

Isothermal molding process leads to high accuracies!
Source: Fraunhofer IPT


An Integrative Approach:
Data Handling
n Data flow (forward): Ideal data flow
– Optic design (IGES file)
Metrology
– FE process simulation
Data
and
NC code generation, both
based on IGES file
– Mold manufacturing
– Molding
n Data flow (feedback)

Data
Metrology
– Metrology data from mold
manufacturing to create
adapted NC code
– Metrology data from
molding to improve FE
process simulation

Source: Zemax, Toshiba, ModuleWorks


Tool making for Precision Glass Molding
Challenges
n High Accuracy (shape deviation < 1µm)

n Optical surface quality (Ra < 10 nm)

n Mold material: carbide
(HV10: 2825 GPa, Density: 15,75 g/cm³)
Process
n Ultra precision grinding
(resolution < 1nm, air guided spindle)
n Resin bonded grinding tools for ductile machining

n 4-axis process for freeform applications

Source: Faunhofer IPT


Precision Glass Molding
Examples

10 mm
5 mm

n Double sided condensor lens for homogenization of coherent (excimer lasers) or
incoherent light sources (ultra high power lamps)
n Appr. 1800 single cavities with optical quality (1.2 mm in diameter)


Machine set-up for ultrasonic assisted turning

control monitor
unit
oszilloscope

HF-generator

spindle
amplifier

personal
computer

adjustable ultrasonic tool system
clamping device
dynamometer

workpiece capacitive sensor


Comparison of Tool Wear in Diamond Cutting –
Conventional Cutting versus Ultrasonic Assisted Cutting
n Conventional cutting n US-assisted cutting
– cutting length < 50 m – cutting length > 5000 m

35µm 35µm

SVy~4 µm SVy~4 µm

rake face rake face
nose radius rε = 0,899mm nose radius rε = 0,899mm

material: X3 CrNiMoAl 13-8-2
depth of cut: ap = 8 µm
feed: f = 5 µm

Ultrasonic Assisted Diamond Tools (40kHz) - The Principle and
Advantages
n diamond tool is loaded 1 vrel > 0 2 vrel = 0 3 vrel < 0 4 vrel > 0 5 vrel > 0 6 vrel = 0
top dead
with ultrasonic vibration in centre
cutting direction bottom
– Amplitude 1 µm dead centre
vc-rot vc-os
– Frequency 80 kHz
6 amplitude [µm]
n reduction of effective point of separation (Ta) (Ta) workpiece
4
contact duration and point of entrance (Te) movement
2
process forces
0 tool
n better inflow of coolant -2 movement
contact
point (Te)
n reduction of friction -4
Ta T Te Ta
between tool and chip -6
0 0,5 1,0 1,5 2,0 2,5 3,5
reduced tool wear contact period without contact contact
ductile cutting contact time [µs]


Molds for micro optics manufacturing
Concave and Convex Aspheres
n Manufacturing on Moore Form deviation [nm]
Nanotech 350 FG
600 PV 144 nm
n On machine measurement 400
200
and compensation applied
0
-200
n Shape accuracies on -400
aspheres < 210 nm -600
-800
-4 -3 -2 -1 0 1 2 3 4
n Tools with non controlled Radial Position [mm]
waviness
Form deviation [nm]

200
PV 204 nm
100
0
-100
-200
-300

-5 -4 -3 -2 -1 0 1 2 3 4 5
Radial Position [mm]


µ-Moulds – Process combinations for new ideas
Demonstrator Mould by the Fraunhofer IPT


µ-Moulds – Process combinations for new ideas
Demonstrator with optimized Top Surface – Microscope Image

burr formation


Your contact to Fraunhofer IPT
Dipl.-Ing. Benedikt Gellissen

Fraunhofer Institute for Production Technology IPT
Steinbachstraße 17, 52074 Aachen
Phone: +49 241 89 04-256
Fax: +49 241 89 04-6256
Mail: benedikt.gellissen@ipt.fraunhofer.de


Palestra 3 - Fabricação de moldes por micro-usinagem.

Recommandé

Recommandé

Contenu connexe

Similaire à Palestra 3 - Fabricação de moldes por micro-usinagem.

Similaire à Palestra 3 - Fabricação de moldes por micro-usinagem. (20)

Plus de senaimais

Plus de senaimais (20)

Dernier

Dernier (20)

Palestra 3 - Fabricação de moldes por micro-usinagem.